Leaders of the federal agency researching the health effects of Camp Lejeune's polluted water are refusing to say if they will launch a sweeping study that could reveal elevated cancer rates among veterans of the Marine Corps base.

"It's a complex kind of approach," Dr. Vikas Kapil, chief medical officer of the Agency for Toxic Substances and Disease Registry, or ATSDR, told the Tampa Bay Times recently. "And it certainly isn't an easy thing to do. It cannot be done quickly."

The agency's reluctance comes amid increasing pressure from members of Congress and former Lejeune residents. Proponents say a second study of Marines who survived cancer may help to better determine the extent of health effects from the North Carolina base's tainted water. It could also provide powerful evidence to sick veterans seeking Department of Veterans Affairs benefits.

The agency's indecision stands in contrast to its earlier statements. The ATSDR's scientists released a report in June 1998 saying a "cancer incidence" study was feasible and could contribute significantly to scientific knowledge about the effects of exposure to pollution.

ATSDR officials say they are still considering doing the study, but critics point out that it has been discussed for at least six years.

"The most important thing is to increase science's knowledge of what diseases these chemicals cause," said Jerry Ensminger, a retired Marine who believes his 9-year-old daughter's 1985 death from leukemia is linked to tainted Lejeune water.

The ATSDR is coming under increased political pressure to launch a cancer-incidence study that would build on a report issued last month that shows Camp Lejeune veterans have died of cancer more frequently than Marines at another base with clean water. Scientists say up to 1 million people, including at least 20,000 Floridians, may have been exposed to water contaminated with chemicals at Lejeune from 1953 to 1987.

ATSDR acting director Dr. Tanja Popovic met Feb. 26 with North Carolina's U.S. senators, Rep. John Dingell, D-Mich., and aides for Sens. Bill Nelson and Marco Rubio of Florida. Lawmakers pressed the agency for the new cancer study.

"The members present in the meeting emphasized our expectation that ATSDR will take this matter very seriously and provide us with a way forward within the month," Dingell said.

Kapil, the ATSDR's chief medical officer, told the Times two weeks ago that he did not have expertise on the proposed cancer-incidence study. Discussion of the pros and cons of such a study would be "speculative and premature" without a full analysis of options, agency spokeswoman Bernadette Burden said.

Members of a panel of veterans and family members advising the agency on Camp Lejeune say it is time to launch the study.

"More information is better," said panel member Lori Freshwater, a Rhode Island woman whose mother died of leukemia after the family lived at Camp Lejeune starting in the late 1970s. "I don't understand the hesitation at all."

A challenge facing scientists, ATSDR documents show, is collecting information from state cancer registries. Data collection can differ among states, and some won't share information due to patient privacy. ATSDR scientists, however, have noted that such studies are difficult but possible.

There is a reason why the air in Tampa Bay is filled with playoff talk. If Thursday night's 12-8 Bucs preseason win over the Jaguars is any indication, it's also going to be filled with footballs thrown by quarterback Jameis Winston.